The Findings (1 of 2)

The main findings of the study were
severe multiple organ damage in rats fed the GM maize and low levels of
Roundup, both separately and in combination. These effects did not become
evident until after the end of the 90-day trial length favoured by industry and
regulators.

1.
Toxicological findings: The main findings were multiple organ damage in rats fed the GM maize,
whether or not the crop had been sprayed with Roundup, and independently, in
rats fed low levels of Roundup in drinking water.

Biochemical analyses of blood and urine was
conducted on the samples taken at 15 months, the latest timepoint when at least
90% of the rats were still alive in each treatment. Statistically significant
damage was found to mammary tissues, liver, kidneys, and pituitary glands of
the rats fed the GM maize grown with and without Roundup, and in the rats given
Roundup in drinking water.

Thus, rat health was impacted – both separately and
jointly – by GM maize and Roundup. Roundup impacts were recorded at exposure
levels permitted in animal feeds in the US and in drinking water permitted in
both the US and EU.

2. Mortality
and tumours: Unexpectedly, both the timing and rate of mortality and
tumour growth were affected by the treatments in this study.

Mortality reflected both spontaneous deaths and euthanasia
due to tumours that impeded functions such as breathing, nutrition, and
digestion. Spontaneous deaths accounted for most male mortality, while euthanasia
accounted for most female mortality during the study.

Male and female rats responded differently to
the GM maize and Roundup treatments. Whereas
30% of control males and 20% of control females died before the mean survival
time, up to 50% of males and 70% of females died prematurely in some groups
containing GM maize. However, the rate of mortality did not
increase proportionately with the treatment dose, reaching a threshold at the
lowest dose (11%) or, for some groups, the mid dose (22%) of GM maize, both with
and without Roundup spraying during treatment.

In males, the maximum difference between
treatment groups and controls was 5 times more deaths occurring during the 17th
month in the group consuming 11% GM maize, and in females 6 times greater
mortality during the 21st month on the 22% GM maize diet with and without Roundup.
In the female treatment groups, there were 2–3 times more deaths compared with
controls by the end of the experiment, and these occurred earlier. Females were
more sensitive to the presence of Roundup in drinking water than males, as
evidenced by a shorter lifespan. The most common causes of death were linked to
large mammary tumours in females, and liver and kidney damage in males.

Three types of tumours were reported: non-regressive
palpable tumours (NRPT), small internal tumours, and metastatic (spreading to
other parts of the body) tumours. As with mortality, tumour incidence appeared
to vary between male and female rats. Small internal tumours accounted for most
tumours in males, and roughly half of those in females, although the proportion
varied among treatments. NRPT in female rats were largely mammary tumours.
Metastatic tumours were rare.

None of the treatments affected incidence of small
internal or metastatic tumours, but all treatments increased NRPT as compared
to the control. Furthermore, NRPT began to occur earlier in treated than in
control rats. For male and female rats, respectively, the first NRPT occurred
at about 700 and 400 days in controls, compared with 100 and 200-300 days in GM
maize treatments, and at around 530–600 and 200–400 days in Roundup-dosed water
treatments.

As explained in subsequent sections, this was
not a carcinogenicity study but a chronic toxicity study, but tumour occurrence
is relevant for two reasons. First, researchers are required to report tumours
even in toxicity studies, according to the chronic toxicity protocol set by the
Organisation for Economic Cooperation and Development (OECD).[1]
Second, specific types of tumours may also be an indicator of specific
metabolic dysfunctions to be explored in further studies.

Nonetheless, of pivotal importance to GMO
safety testing is the timing of the tumour onset. The first NRPTs were detected
at 4 and 7 months for male and female rats respectively, with most tumours
occurring after 18 months. This illustrates the futility of relying on 90-day
feeding trials to detect potential risks from chronic exposure to GMOs and
their associated pesticides.

[1]
Organisation for Economic Cooperation and Development (OECD) (2009). OECD
guideline no. 452 for the testing of chemicals: Chronic toxicity studies:
Adopted 7 September 2009. http://bit.ly/LxJT1Z Note: The OECD uses the word “lesions”, which
would include tumours.